Alloy



July14, 1942. C, a SAWYER EN; 2,289,593

' ALLOY Fiied Aug. s, 1940 Afro/mfr Patented July 14, 1942 v2,2zas93Charles B. Sawyer, Cleveland Heights, Bengt R.` A F. Kjellgren,University Heights, and Gerald G Christensen, Cleveland, OhioApplication August 3, 1940, Serial No. 350,780

1o claims..y (cl. 14s-e2) This invention relates to beryllium copper a1-loys containing nickel, and it relates more especially to such alloys inwhich the copper is more than about 90%, and the nickel' and berylliumtogether amount to. lesshthan about 5%.

Beryllium copper alloys containing nickel form" *the subject of severalpatents which have been fgrantedinthe past. United States Patent No.

1,393,984,1ssued to yCorson, is the earliest United States patent whichrelates to .alloys of the type here under` i consideration. It.`discloses ternary copperberylliumnickel f alloys whichl may con- .tainup toA about` 2% beryllium and up to as `much as v40% nickel. Otherpatents issued subsequently have dealt with other ranges of berylliumand nickel in ternary alloys, while still others have been concernedwith quaternary alloys in .which the nickel and beryllium ranges havebeen diversified, and in` which various fourth-metal alloying additionshave `been in-` cluded. `While a Wide range of mechanical properties.can be obtained in these prior alloys, depending on the l relativeproportions of the 'various alloyingelements of each, few of the alloyshave possessed maximum'electrica'l conductivities .of much over fiftyper cent of that of copper. The

few that have` conductivities in excess of this Y latter `value contain`relatively large amounts of alloying ingredients which are .considerablymore expensive than nickel, and in` addition possess certainmetallurgicall characteristics `which militate againsttheir use undersome conditions.

f moderate hardness` with resistance' to wear or" alloy of the classdescribed which may be cast readily into intricate shapes.

kIt is another object to provide` an improvedA alloy of the classdescribed which may be fabricated readily from the cast condition vbymeans Y of any of the usualprocesses of forging. rolling,` hammering,drawing, extruding, etc.

Numerous industrial/devices and 'apparatus4 require parts which-are'made of material havim; good electricalconductivity and possessingabrasion. Weldingelectrodes` of'various types exemplify such uses..vCopper e alloys' have, in general, beenmost successful, in meeting theneeds of such applications. `Few copper base1 alloys. however, haveadequatehardness together4 loys are more than adequatetov meet therequirel with adequate `electrical conductivity. It has been known for anumber of years that copper may be heat-hardened when itis alloye'd withsmall amounts of beryllium.v The values .of hardness obtainable insuchbina'ry-beryllium copper alments of the appucations Imentioned,above.

It is a primary objectfof -this invention to pro- I vide an improvedberyllium copper alloy in which nickel is the basic third-'metaladdition but in which fourth-metal additions may also be included eitherto enhance the effects of the nickel or to improve the'alloy in some ofits metallurgi'` cal aspects Without diminishing appreciably theadvantages to begained from the primary nickel addition.

It is another primary object to provide an alloy r of the classdescribed which possesses improved electrical conductivity.

YIt is another primary object to provide an agehardened alloy oftheclass described. which possesses high electrical conductivity togetherwith desirable mechanical ,properties such as strength, hardness,proportional limit, fatigue limit, abrasion resistance, etc.

It-is another object to provide an improved alloy of the class describedwhich is suitable for use as an electrical conductor in'both the ascastunheat-treated condition, and in its numerous heat-treated conditions.

It is a further object to provide a pressure welding electrode composedof 'an improved agee hardened alloy of the class described.

It isanother object to provide van improved `are introduced into thebinary alloys. y

pointed out in the patent referred 'to above that However, such binaryalloysv do Anot .have suitable electrical conductivities. Furthermore;such binary alloys are unduly expensive `since beryllium contents ofaround 1.0% Vor more are necessary to provide the- .hardening effect. Ithas also been known for a number of vyears'that the amount of berylliumrequired tol harden` copper `can be materially reduced Lif various thirdmetals Corson nickel is a third-metal addition to beryllium copper whichAhas this effect. Other workers have shown that several other elementsalso have the same kind of effect.'` When the properites of thesevarious ternaryberyllium copper alloys became known, it seemed likelythat they would'be able to meet thefrequirements of hard, ness andelectrical conductivitywhich are involved in the previously mentionedapplications.

It has been found, however, that few of the -ternary alloys or even ofthe more complex alloys of copper and beryllium have values ofele'ctrical conductivity and hardness which are desired. In theberyllium-copper-nickel alloys in particular, Corson has indicated -thatconductivities of around 33% may-be expected in such alloys after theyhave beenworked and precipitation-hardened to a, condition which givesthe alloy suitable mechanical properties. i The hardness of the alloy`has been indicated to be around Brinell. It has commonly beenconsidered that while greater hardness values might be ob,- tained inthe Corson alloys, conductivities in excess of the value stated couldnot be expected,

'this being on the general theory that as the hardness is increased,Athe conductivity is decreased. However, in investigating the low beryl-'in" a restricted range. of values.

lium alloys ot Coxon-Anelli, we lhave foun that exceptionally goodelectrical conductivities can be obtained along with desirablevalues ofl hardness by 'suitably proportioning the beryllium andnickel-contentsoi the alloys.

` This invention is based on the discovery that an improved alloyresults if the nickel and beryllium contents are proportioned to fallwith- The improved alloy which results is characterized by highelectrical conductivity, particularly after a precipitationheat-treatment. and by a desirable range oi' mechanical andmetallurgical properties which adapt it for use in numerous tields ofapplication. Preferred compositions lying within the limits ot theIinventionare particularly adapted j for use as pressurefexertingwelding electrodes. Qther preierredcompositions are adapted for use inunheat-treatedcastings which should, in use, strength, hardness and goodelectrical or-thermal conductivity. Still other preferred compositionslare adapted for use in applications which require exceptionally highelectricalor thermal conductivity with only mod,- erate strength or Allcompositions. falling within the limits of the invention arecharacterized by their susceptibility to precipitation hardeningheat-treatments, and by their capacity for being fabricated by the usualmetal working methods and apparatus. When the alloys are so fabricatedand suitably heat-treated, they even hig er 'values of electricalconductivity than can obtained in the as-cast heat-treated metal. l

',The invention will be `understood more fully lium, by increasing thenickel proportionatelyiasYV the beryllium/ content is increased. This ismerely a general statement. however, ior it will be observed lthat itdoes not apply strictly to the whole iield of the invention. It will benoted particularly, however. that the increase in'nickel content isnearly a linear function of the in. crease inberylliumcontent in theparticular region which is adjacent to the diagonal line M -M'. Anlinvestigation of this region has shown that an optimum ratio prevailsbetween the nickel and beryllium contents. It has `been throughreference to \the accompanying drawing which illustrates graphicallyth'e approximate limits of the invention together with typical values ofelectrical conductivity which may be obtained lin as-c` t age-hardenedalloys having suitable propo ions between the beryllium and nickelcontents' thereof. 'lhe limits of the inf vention aref-,marked by thevclosed traverse ABCDEFGHJQ.' and the electrical conductivities of alloysfalling within theapproximate ileld of invention are shownby means ofcontours which mark theapproximate outer limits of regions in which maybefobtained at least the electrical conductivity which is indicated bythe index number of each contour.l It will be understood that theindexnumber represents the conductivity measuredin per cent of theconductivity oi' standard, copper. Thus, an index number of 50 indicatesthat in'therileld bounded by the "50 contour, electrical conductivltiesof 50% or more are obtainable. 'I'he conductivitles indicated inthedrawing were measured at abopt 23 C., and represent-values which may beobtained in an as-cast, unworked alloy having the indicated berylliumand nickel contents. Prior to measurement, each composition wassubjected to an age-hardening heat-treatment consisting tained in alloyscontaining asnuch as .8% beryl- 4following formula:

foundthat the ratiol maybe expressed by the nickel minus 0.25=

beryllium 5 When the proportions of nickel andk beryllium complyapproximately with this formula, better values ofelectrical conductivitycan be secured than in alloys which do not comply therewith.

It has been pointed out above that the contours of the drawing markapproximate outer limits of areas of composition which contain alloyscapable of possessing electrical conductivities of indicated values.ciated, however, that while the contours are based on and derived fromconductivity measure.- ments of numerous alloys which fall within thescope of the invention, yet the contours are only' careful estimates offields of alloy compositions,

expressed graphically rather than verbally. They should be regarded morein the nature of guides to the ileld of composition which represents theinvention, rather than being regarded as exact graphical delineations ofprecise critical boundaries between iields of composition. In otherwords, it should be' recognized that the contours may be subject to somedegree of correction as the number of conductivity measurements 'ofdistinct alloyA compositions is extended throughout the ileld of theinvention.

Through reference to the drawing it will bev observed that when linesare drawn to connect the points A, B, C, D, E, F, G, H, J, and A insuccession, a closed traverse is formed which encloses the field ofdiscovery which represents the invention. Furthermore, it will beobserved that the area of compositions so enclosed includes alloyswhich, for the most part, have electrical conductivlties of-50% or moreafter they have been subjected to the particular heat-treatment on whichthe drawing is based. Included within the closed traverse ABCDEFGHJA areother areas which include alloys capable of being heattreated so as topossess electrical conductivlties l of,v for example, 60%, 65%, or 70%or more. Specific 'examples selected from these various areas aredescribed below, where it will be seen that the alloys possess otherdesirable mechanical properties in addition to' these exceptionally highconductivlties.

One area containing compositions whichare of particular merit is thearea bounded by the traverse ABCDEFGA. 4Another area which constitutes.av preferred portion of the invention is the area which includes alloyscontaining from about .75% nickel to about 2.0% nickel with berylliumcontents `falling within the limits of the invention as marked by thetraverse ABCDEFGHJA. Still another preferred range lies within theclosed .traverse ABCDEFGHJA, but includes alloys which contain fromabout .75% nickel to about 2.0% nickel, and from about 0.20% beryl-l Itshould be appre` com to about .45% beryllium. ancora .een or alloyshaving meritior particular uses is the field of the invention whichllies between about .05% beryllium and about .20% beryllium, with asso,

ses

heated at 900.- C. for one hour and quenched, and reduced` in'area about00% by coldedravving. The material was then tested in the afs-drawnvcondition and in several ass-drawn and heatniclrel between about .25%and about l.'l5%. 5 treated conditions with thefollowing results; Stillanother compositional ileld containing al- A Table lll loys havingoutstanding properties is the held marlred by traverse BCDEFGB withnichel con@ TG SH@ wel@ me tents above about 2%. n preferred rangewithin L) (p gl L) mnd: this latter neld is bounded by the traverse andl by nichel contents or more than about 2% and Pefcem less than about3.75%." The following speelde Asdrwn 72.000 07.000 39-0 1 s examplesselected from each oi these indicated ggg g1 Zggg iglg c4713 fields willprovide a more complete understand- -Asdrawnand aged 211mm@ 500 G-115,000 80.000 M0 lng of the merits of the alloys oi the invention. 1'5Y Taatu irais-cast alloys L,

Tensile Yield alcnga- Elec. Banen Be Ni Treatmnt (p. s. 1.) (p. s. 1.)tion cond. hardness l iercent .69 3.30 Quenched from 900 C.; aged 2hours 500 C f 50.9 Quenched from 900 C.; aged 2hours 400 C. j 48. l.v.4s-cast; not heat-treated; 45, 0 ..59 2.78 As-cast; not heat-treated40.5 Quenched from 900 C.; aged v2 hours 50 C I 5l. 4 .23 1.47 As-cast;not heat-treated 45,5 Qucnched from 900 C.; aged Zhours 550 C 57. 7 .23-1.48 As-cast; not heat-treated 42 Qnenched from 900C.; aged 1 hour 450 C86, 500 52, 500 53 .22 1.49 `As-oast; not heat-treated 30,000` ,000 39 AQuonched from l,000 C.; aged 2 hours 500 C- 80, 000 00, 000 61. 5 200.28 1.139 Quonched from 900 C.; aged 2hours 500 0-.... ,000 60,000 53.0200 .13 .74 As-cast;n0theattreated 49.0

. Qucnched from l,000 C.; aged 2hours @500 0....I f 7310 Quenched from900 C.; aged 4 hours 475 C. 51, 400 37, 250 71. 2 124 *Pounds per squareinch. v

The following examplesillustratethe improvements in properties andvconductivity which can be obtained by subjecting the as-cast alloys ofthe invention to mechanical working treatments of various kinds.- v

An alloy containing .32% beryllium and 1.47% nickel was quenched fromabout 900 C. and vwas then forged cold to about 80% of its originalcross-sectional area. The forged material was subsequently aged byheating it at 450 C. for two hours. Its electrical conductivity in thisage-hardened condition was 69%. This may be compared with a.conductivityof about 55% in the as-cast condition after having beenage-'- hardened by quenching from about 900 C. and

.Y reheating for two hours 'at 500 C.

A cast ingot analyzing .25% beryllium and The other half of the abovelot of the .12.8" diameter cold-drawn materiall was heated atv 750 C.for one hour, quenched, and reduced in area'about40% `by cold-drawing.The following results indicate the nature of the material.

Table IV 'Tensile Yield Elec. (p. s. 1.) cond.

l v Peiv cent As drawn 72, 000 I 59.8 As drawn and aged 2 hours 450 C80, 000 64, 000 70. 8

It will be noted that the worked alloys have very desirable propertiesin both the as-worked and in the .Worked and heat-treated conditions.

' It will also be noted that the electrical conduc- 1.33% nickelwasquenched after having beenheated for three hours at 900 C. Thequenched ingot was then hot-rolled at about 900.C. to a.

diameter of 5/16 inch. The rolled material was again heated to 900 C.and quenched, and then cold drawn from lihe" to .178 diameter. Theproportional limit of the latter material wasdetermined, V18" samplesbeing used. The following table indicates the results' obtained undertivity of alloys of the invention may be improved considerably byworking them, and especially by age-hardening the "quenched and workedmaterial.

It 'will be understood from the above examples'. that the alloys 'of theinvention possess diverse properties which make certain compositionalgroups vmore 'suitable for some `uses than for others. In general,alloys of the invention which contain less than about '2% nickel andmore than ,about .2% beryllium are particularly adapted for use inelectrical conductors of all kinds which various conditions ofheat-treatment.

` TABLE 1I Tensile (p. s. i.) (p. EL i.)

As quenched from 900 C 43,000 4, 700 As quenched from 900 C.; aged 2hours 40 C 91,000 46,000 As quenched from 900 C.; aged 2 hours 425 C102, 500 55,800

require high electrical conductivity together with hardness andresistance to fatigue. yBy reason of-their high proportional limits,these alloys make good current-conducting springs. By reason of theirhardness, strength, and electrical conductivity, they are especiallygood for use in pressureexerting-welding electrodes of all kinds, andfor many useswhere abrasion` and wearresistance 'are desired. Motor and.generator slip-rings exemplify the latter uses.

Alloys of the invention which contain more than about.2% nickel areespecially useful in making articles which are used in their as-castcondition and which need good electrical or thermal conductivities. Thealloys are extreme fluid in thevmolten state-and can be readilycast intointricate shapes.l Furthermore, the alloys have nearly as good values ofconductivity inthe -as-cast condition as in the usual heat-treatedconditions. It will be understood, of course, that `the conductivity ofan alloy in the as-cast condition is determined to a large extent by thecasting conditions. If the molten metal is solidified in a chill mold,its conductivity will be somewhat low and its properties are more apt toapproach the `properties of as-quenched material. If the metal issolidified in` a sand mold where it is cooled more slowly, theconductivity will be higher and the properties will approach theproperties of material which has been age-hardened slightly.

It has been indicated above that alloys containing between about .05%and .20% beryllium, and nickel between about .25% and 1.75% constituteanother preferred eld of the invention. It will vbe observed from TableI that alloys in this'iield have moderate values of strength andhardness in age-hardened as-cast or worked conditions. In addition, theypOSsesS unusually high electrical and thermal conductivities. By reasonof these .properties the alloys of the eld are especially suitable formaking hammered or forged articles which require exceptionally highconductivities without unusually high strength or hardness. Many partsof electrical and thermal instruments. machines, and apparatus involvesuch requirements.

Those skilled in the art will appreciate that the merits ofcopper-beryllium-nickel alloys of the invention may be retained eventhough the alloys contain appreciable amounts of other metals orelements. Such other constituents may .be added to enhance the effectsof the nickelberyllium proportions of the invention and/or to improvediverse metallurgical characteristics of the alloys without impairingone or more of the electrical, thermal or mechanical propertiesappreciably.

Reference has been made in the preceding speciflcation to the thermalconductivities of alloy compositions of thev invention. Inasmuch as ithas long been'an established fact that thermal and electricalconductivities of most metals parallel .each other closely under mostconditions,`

the electrical conductivities indicated throughout the specification maybe regarded as beingclose approximations also oi relative thermalconductivity.

Having now disclosed `the invention, what we claim is:

1. A copper base alloy containing beryllium and nickel in amounts whichfall substantially within the graphical area of composition bounded bythe closed traverse formed by joining the following points in sequence:from .05% beryllium at .25% nickel, thence to .05% beryllium at 1.5%nickel, thence to .35% beryllium at 3.0% nickeL thence to .70% berylliumat 4.25% nickel,

'thence Yto .80% beryllium at 4.25% nickel, thence to 80% .beryllium at3.75% nickel, thence 'to .475% beryllium at 2.0% nickel, thence to .55%beryllium at 1.25% nickel, thence to .30% beryllium at .25% nickel,thence to the starting point of .05% beryllium at .25% nickel, thebalance being substantially all copper.

2. An alloy as claimed in claim 1 wherein the nickel and beryllium arepresent in approximately the following ratio: f

% nickel minus 0.25 5

% beryllium 3. An alloy as claimed in claim 1 wherein the berylliumcontent is between about .2% and .4%, and the nickel content is lessthan 2.0%.

4. An alloy as claimed in claim 1 wherein the nickel content is morethan 2.0%.

5. An age-hardened copper base alloy containing beryllium and nickel inamounts which fall substantially within the graphical area ofcomposition bounded by the closed traverse formed by joining thefollowing points in sequence: from .05% beryllium at .25% nickel, thenceto .05% beryllium at 1.5% nickel, thence to .35% beryllium at 3.0%nickel, thence to .70% 'beryllium at 4.25% nickel, thence to ,8%beryllium at 4.25% nickel, thence to .8% beryllium at 3.75% nickel,thence to .475% beryllium at 2.0% nickel, thence .to .55% beryllium at1.25% nickel, thence to '.30%

beryllium at .25% nickel, thence to the starting point of .05% berylliumat .25% nickel, the balance being substantially all copper.

6. An age-hardened alloy as claimed in claim 5 wherein the nickel andberyllium are present in approximately the following ratio:

% nickel minus 0.25 5

% beryllium 7. An age-hardened alloy as claimed in claim 5 wherein theberyllium content is between about .2% `and .4% and the nickel contentis less than ductivity of standard copper after the said alloy has beenage-hardened by subjecting it to a solution heat-treatment at,about 900C., quenching.'

and reheating for approximately two hours at 500 C.

9. A casting made ofthe alloy as claimed in claim 1 wherein the nickelcontent is between about 2% and 4.25%.v

10. A pressure-exerting welding electrode composed of an age-hardenedalloy as claimed in 4claim 5, said electrode being characterized by anelectrical conductivity of more than about 50% of the conductivity ofstandard copper after the said electrode has been age-hardened bysubjecting it to a solution heat-treatment at about 900 C., quenching,and reheating for approximately two hours at 500 C.

CHARLES B. SAWYER. BENGT R. F. KJELIGREN. GERALD G. CHRISTENSEN.

